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CVE-2026-125729EUVD-2026-121395

Plack::Middleware::CSP versions before 0.03 for Perl send the Content Security Policy under the wrong header name, so browsers never…

Exploited
No known exploitation
Fix
Fixed in 0.03
Who is exposed
Not reported

Do first: Upgrade to a fixed version: 0.03.

Published
Last modified
Reference
Last checked
0/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

Plack::Middleware::CSP for Perl sends its Content Security Policy under a misspelled header name that browsers ignore, so the policy is never enforced. Any cross-site scripting flaw in the wrapped application can therefore run scripts that the policy was meant to block.

Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.

Read the original description

Plack::Middleware::CSP versions before 0.03 for Perl send the Content Security Policy under the wrong header name, so browsers never enforce it.

The call method sets the policy in a response header named "content-security-protocol" instead of "Content-Security-Policy". Browsers ignore that header.

Any cross-site scripting flaw in the wrapped application can run scripts the policy was meant to block.

cve.now Index

0Pcve.now Index 0 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure?/25Unknown. No advisory context yet
  • Reach?/20Unknown. No tracked technology or package matched
  • Severity?/10Unknown. No CVSS score or vendor rating
  • No patch0/5No signal

What would change the score

  • Would score about 55 if added to CISA KEV
  • Would score about 50 if CISA's SSVC rates exploitation active
  • Would score about 22 if advisories confirm default setups are exposed

How the score works · Rankings

What to do

  • Upgrade to a fixed version: 0.03.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by CVE-2026-125729 (Plack::Middleware::CSP versions before 0.03 for Perl send the Content Security Policy under the wrong header name, so browsers never…), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-125729 (entry last updated 2026-11-10):
Affected:
- Plack-Middleware-CSP: fixed in 0.03
Fixed versions: 0.03.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-125729 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-125729 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/pangyre/Plack-Middleware-CSP/issues/1
- https://metacpan.org/release/ASHLEY/Plack-Middleware-CSP-0.03/source/CHANGES
- http://www.openwall.com/lists/oss-security/2026/11/10/16
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-125729
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-125729.

Timeline

  1. CVE published
  2. First seen by cve.now
  3. Record last updated

Affected versions

  • Plack-Middleware-CSP

    fixed in 0.03

Evidence 5

CVE record · 2

Establishes: The identifier and description.

  1. Record
  2. Record

Write-ups · 1

Establishes: Technical detail and context.

  1. Link

Other links · 2

  1. Report
  2. Link

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-125729

Is CVE-2026-125729 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by CVE-2026-125729?

Plack-Middleware-CSP: before 0.03.Source: cve.now feed data

How do I fix CVE-2026-125729?

Upgrade to a fixed version: 0.03.Source: cve.now feed data

Sources

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